<?php
/**
 * Created by PhpStorm.
 * User: admin
 * Date: 2018/4/6
 * Time: 16:42
 */

namespace app\api\server;


use app\lib\exception\TokenException;
use app\lib\exception\WeChatException;
use think\Exception;
use app\api\model\User as UserModel;

class UserToken extends Token
{
    protected $code;
    protected $wxAppID;
    protected $wxAppSecret;
    protected $wxLoginUrl;

    function __construct($code)
    {
        $this->code = $code;
        $this->wxAppID = config('wx.app_id');
        $this->wxAppSecret = config('wx.app_secret');
        $this->wxLoginUrl = sprintf(config('wx.login_url'),
            $this->wxAppID, $this->wxAppSecret, $this->code);
    }

    public function get()
    {
        $result = curl_get($this->wxLoginUrl);
        $wxResult = json_decode($result, true);

        // 根据微信的借口返回结果总结暂时较为完整的
        if (empty($wxResult)) {
            throw new Exception('获取session_key及openID时异常，微信内部错误');
        } else {
            $loginFail = array_key_exists('errcode', $wxResult);
            if ($loginFail) {
                $this->processLoginError($wxResult);
            } else {
                return $this->grantToken($wxResult);
            }
        }
    }

    private function grantToken($wxResult)
    {
        /**
         * 拿到openid
         * 数据库看下，openid是否已经存在
         * 存在 不处理，不存在 新增一条user记录
         * 生成令牌 准备缓存数据 写入缓存
         * 把令牌返回到客户端去
         * key: 令牌
         * value：wxResult, uid, scope
         */
        $openid = $wxResult['openid'];
        $user = UserModel::getByOpenID($openid);

        if ($user) {
            $uid = $user->id;
        } else {
            $uid = $this->newUser($openid);
        }
        $cachedValue = $this->prepareCacheValue($wxResult, $uid);
        $token = $this->saveToCache($cachedValue);
        return $token;
    }

    private function saveToCache($cachedValue)
    {
        $key = self::generateToken();
        // 数组对象 -> str
        $value = json_encode($cachedValue);
        $expire_in = config('setting.token_expire_in');

        $request = cache($key, $value, $expire_in);
        if(!$request) {
            throw new TokenException([
                'msg' => '服务器缓存异常',
                'errorCode' => 10005
            ]);
        }
        return $key;
    }

    private function prepareCacheValue($wxResult, $uid)
    {
        $cachedValue = $wxResult;
        $cachedValue['uid'] = $uid;
        $cachedValue['scope'] = 16;
        return $cachedValue;
    }

    private function newUser($openid)
    {
        $user = UserModel::create([
            'openid' => $openid
        ]);
        return $user->id;
    }

    private function processLoginError($wxResult)
    {
        throw new WeChatException(
            [
                'msg' => $wxResult['errmsg'],
                'errorCode' => $wxResult['errcode']
            ]
        );
    }
}